Film Coatings Based on Polyalkylimine Condensation Polymers

ABSTRACT

Provided is a composition, preferably VOC-free, comprising the condensation product of a polyalkylimine and one or more amine-reactive molecules, and films coated with the condensation product. The coatings are applied to the films to provide a dried coating weight of less than 0.30 g/m 2 . Preferred amine-reactive molecules include acetylacetonate, methyl acetonate, ethyl acetoacetonate, glycidyl methacrylate, methyl methacrylate, and mixtures thereof.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to PCT/US2011/030345 filed Mar.29, 2011, and to U.S. Provisional Patent Application 61/540,802 filed onSep. 29, 2011.

FIELD OF THE INVENTION

The present invention relates to film coatings to promote printing inkadhesion, and more particularly to film coatings based on condensationpolymers of polyalkylimines.

BACKGROUND

Current clear pressure sensitive film labels work very well, but oftencontain volatile organic compounds (“VOCs”) that constrain the allowedcoating weights. Moreover, a key raw material in prior art coatings,such as disclosed in U.S. Pat. No. 6,893,722, is often limited in thenumber of suppliers in the market. Therefore, there is a need for newerfilm coatings that reduce the VOCs and for which the raw materials areless specialized.

The inventor has found a way to retain some essential advantages ofcoatings, as in U.S. Pat. No. 6,893,722, that yield excellent UVprintability and print durability (IPA resistance, pasteurizationresistance, etc.) but without VOCs and without the need of a complexcondensation/grafting process (and the associated equipmentconstraints). Moreover, the new technology described herein appears tooffer utility beyond just pressure sensitive labels. Due to theirchemical composition and efficacy at extremely low coating weights, thecoatings described herein offer a broad range of film applications.

Related prior publications include U.S. Pat. No. 6,297,328; U.S. Pat.No. 5,296,530; U.S. Pat. No. 5,525,662; U.S. Pat. No. 5,498,659; U.S.Pat. No. 5,811,121; U.S. Pat. No. 5,380,587; U.S. Pat. No. 5,382,473;U.S. Pat. No. 5,419,960; U.S. Pat. No. 5,789,123; U.S. Pat. No.5,827,627; and US 2011/0254909 and US 2007/0248810A1.

SUMMARY

Provided is a composition comprising the condensation product of apolyalkylimine and one or more amine-reactive molecules comprising (orselected from the group consisting of in another embodiment) at leastone of:

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂  (1)

or (and)

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂  (2)

where Y is halogen or a three-membered oxirane ring; R^(a) and R^(b) arethe same or different and selected from the group consisting of H and C₁to C₆ alkyl; R^(c) is selected from the group consisting of O and CX₂;each X can be the same or different and is selected from the groupconsisting of H, hydroxyl, halogen, and any organic radical containingat least one carbon atom, wherein each R^(d) can be the same ordifferent; A is selected from the group consisting of O and NR^(d);CR^(d) and CR^(d) ₂ can each be a separate moiety or a portion of acyclic structure; j, k, and m are integers ranging from 0 to 6,inclusive; q is an integer ranging from 1 to 6, inclusive; and p is aninteger ranging from 0 to 30, inclusive.

Alternatively, the moieties above for formulas (1) and (2) can bedefined where Y is halogen or a three-membered oxirane ring; R^(a) andR^(b) are the same or different and are H or a C₁ to C₆ alkyl;R^(c l is O or CX) ₂; each X can be the same or different and is H,hydroxyl, halogen, or any organic radical containing at least one carbonatom, wherein each R^(d) can be the same or different; A is O or NR^(d);CR^(d) and CR^(d) ₂ can each be a separate moiety or a portion of acyclic structure; j, k, and m are integers ranging from 0 to 6,inclusive; q is an integer ranging from 1 to 6, inclusive; and p is aninteger ranging from 0 to 30, inclusive.

Also provided is a film comprising at least one polymer layer having afirst and second side, further comprising a coating on at least thefirst side, wherein the coating is the condensation product of apolyalkylimine and one or more amine-reactive molecules comprising (orselected from the group consisting of) at least one of:

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

or (and)

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

where each group has the same meaning as above.

The various descriptive elements and numerical ranges disclosed hereincan be combined with other descriptive elements and numerical ranges todescribe the invention(s); further, any upper numerical limit of anelement can be combined with any lower numerical limit of the sameelement to describe the invention(s).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical representation of tests showing the relationshipbetween the coating weight (on a test film) of an inventive condensationpolymer versus its adhesion (0-Ink-2 method).

FIG. 2 is a graphical representation of tests showing the relationshipbetween the coating weight of an inventive condensation polymer versusits adhesion having had prior UV exposure (5-Ink-2 method).

FIG. 3 is a graphical representation of tests showing the relationshipbetween the coating weight of an inventive condensation polymer versusits adhesion in water (0-Ink-2).

FIG. 4 is a graphical representation of tests showing the relationshipbetween the coating weight of an inventive condensation polymer versusits adhesion in water having had prior UV exposure (5-Ink-2).

FIG. 5 is a graphical representation of tests showing the relationshipbetween the coating weight of an inventive condensation polymer and theblocking force of the film having the coating thereon.

DETAILED DESCRIPTION

Disclosed herein are compositions comprising the condensation product ofpolyalkylimines with certain amine-reactive molecules, thus formingcondensation polymers. The compositions tend to form soluble orsubstantially soluble compositions in aqueous media at and above pH 8.By “aqueous”, what is meant is a diluent comprising at least 50 wt % or60 wt % or 70 wt % or 80 wt % water, and preferably comprising at least95 wt % or 100 wt % water. The compositions are particularly useful ascoatings on films. Such coatings are present in a sufficient amount toenhance the printability of ink on the film surface, and preferably, tomaintain the ink on the surface for extended periods with typical wearand moisture conditions. The coatings can be a primer, which is acoating layer that is in between the primary printable coating and thefilm to enhance the adhesion of the printable coating to the filmstructure. The coatings may also serve as the primary printable coatingitself In either case, one advantage of the condensation polymers isthat they require very low loadings compared to current coatings. Incertain embodiments, the coating weight on the film surface (either as aprimer or as the primary printable coat) is less than 0.30 or 0.20 or0.15 or 0.10 g/m²; or within the range from 0.001 or 0.01 to 0.10 or0.15 or 0.20 or 0.30 g/m².

Another advantage to the coating compositions described herein is thatthey are free of volatile organic compounds (“VOC”). Thus, in certainembodiments are described compositions and coatings that are free ofVOCs. VOC's are organic chemicals that have a high vapor pressure atordinary, room-temperature conditions, non-limiting examples of whichinclude formaldehyde, ethyl alcohol, hexane, terpenes, toluene, andacetone.

In one aspect is a composition comprising the condensation product of apolyalkylimine and one or more amine-reactive molecules comprising (orselected from the group consisting of in another embodiment) at leastthose in formulas (1) and (2):

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂  (1)

(and)

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂  (2)

where Y is halogen or a three-membered oxirane ring; R^(a) and R^(b) arethe same or different and selected from the group consisting of H and C₁to C₆ alkyl; R^(c) is selected from the group consisting of O and CX₂;each X can be the same or different and is selected from the groupconsisting of H, hydroxyl, halogen, and any organic radical containingat least one carbon atom, wherein each Rd can be the same or different;A is selected from the group consisting of O and NR^(d); CR^(d) andCR^(d) ₂ can each be a separate moiety or a portion of a cyclicstructure; j, k, and m are integers ranging from 0 to 6, inclusive; q isan integer ranging from 1 to 6, inclusive; and p is an integer rangingfrom 0 to 30, inclusive.

In one embodiment, R^(c) is oxygen (O); R^(a) and R^(b) is methyl or H;X and R^(d) is hydrogen (H); j is 1; k is 0; q is 2; p is 1; and A isoxygen (O). In another embodiment, Y is a three-membered oxirane ring(CH₂(O)CH₂); m is 1; p is 0; A is oxygen (O); R^(b) is methyl (—CH₃);and X is hydrogen (H). In desirable embodiments, the amine-reactivemolecule is selected from the group consisting of acetylacetonate,methyl acetonate, ethyl acetoacetonate, glycidyl methacrylate, methylmethacrylate, and mixtures thereof

The polyalkylimine (“PAI”) can be any oligomer or polymer, or mixturethereof, having at least one “imine” group (—N(H)—) incorporatedtherein. Desirably, the imine group(s) is part of the polymer backbone.In one embodiment, the polyalkylimine is an imine containing polymercomprising C₂ to C₁₀ alkyl or alkenyl-derived units in the backbone.Preferably, the PAI comprises imine-derived units and alkyl-derivedunits, and most preferably, the PAI consists of imine groups andalkyl-derived units. Preferably, the PAI is selected from the groupconsisting of polyethyleneimine, polypropyleneimine,polypropyl-co-ethyleneimine, and mixtures thereof In particularembodiments, styrenic-derived units, such as present in styrenatedacrylic resin, are absent from the polyalkylimine. In any case, the PAIpreferably has a weight average molecular weight (M_(w)) of from 3,000or 5,000 or 10,000 or 20,000 or 40,000 to 80,000 or 100,000 or 150,000or 200,000 or 300,000 or 500,000 or 1,000,000 or 2,000,000 amu.

The condensation polymers described herein are typically produced in anaqueous solution by combining the amine-reactive molecules with a PAI.Amine-reactive molecules are molecules that include at least one moietythat will react with an amine/imine to form a covalent or ionic chemicalbond, preferably covalent. Desirably, there are from 0.1 or 0.2 to 0.6or 0.8 or 1.0 or 1.1 or 1.2 or 2.0 or 2.5 or 3.0 amine-reactiveequivalents (“ARE”) of the amine-reactive molecules that are combinedwith the PAI. Desirably, the product can be isolated from an aqueousdiluent in solution or substantially in solution at a pH of at least 8.The product of the condensation reaction between the PAI andamine-reactive molecule is the condensation polymer as described herein,but in certain embodiments it is not necessary to specifically isolatethe condensation polymer from the reaction medium, hence, in certainembodiments, the usefulness of the condensation polymer is as the entiremixture or condensation product. The condensation polymer can be usedfor coating in solutions or suspensions at most any pH, and in certainembodiments, the composition, when used as a coating, is a suspensionhaving a solids content within the range of from 0.1% or 0.5% or 1% to3% or 4% or 5% or 8% or 10% or 30% or 50% or 60%, by weight of thecoating.

The PAI coatings of the invention may also be further modified orcross-linked by either chemical means or radiative means. Secondaryalkylamines are known to undergo Michael-type additions reactions atroom temperature with ethenically unsaturated compounds like methylacrylate, acrylonitrile, and many other materials with similarfunctionality (Mather et al., 31 Progress in Polymer Science, 487-531(2006)). Typical Michael-acceptors that are α, β-unsaturated carbonylcompounds are thus preferred in cross-linked PAIs to further modify orcross-link PAIs. Examples of non-cross-linking Michael-type PAImodifiers include acrylates (for example, methyl acrylate,2-hydroxyethyl acrylate, acrylamide) or acrylonitrile. To significantlyincrease the molecular weight of the PAI, the polymer can becross-linked with poly-functional acrylates such as 1,6-hexanedioldiacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate(PETA), or other readily available materials, some of which containvarying degrees of ethoxylation or propoxylation.

A desirable use of the condensation product is in coatings for films.Thus, in one aspect of the invention, described herein is a filmcomprising at least one polymer layer having a first and second side,further comprising a coating on at least the first side, wherein thecoating is the condensation product of a polyalkylimine and one or moreamine-reactive molecules selected from molecules of formulas (1) and (2)as described above. The “film” can be made of most any material and canbe multiple layers of materials as is known in the art. Desirably, thecondensation product is adhered to at least one external surface of thefilm, understanding that any film in two-dimensions (ignoring itsthickness) will have two external (first and second) surfaces. Thus, inone embodiment, the first and second sides of the film are coated withthe polyalkylimine condensation product.

More specifically, in one embodiment, the film is a multi-layered filmhaving outside surfaces on both sides of the film, wherein both of theoutside surfaces are coated with the polyalkylimine condensationproduct. In certain embodiments, as mentioned above, the coating weightof the condensation product once dried on the film surface (first orsecond) is less than 0.30 or 0.20 or 0.15 or 0.10 g/m²; or within therange from 0.001 or 0.01 to 0.10 or 0.15 or 0.20 or 0.30 g/m².

In any case, in certain embodiments, the polymer used to make the filmis selected from the group consisting of polyethylene, polypropylene,ethylene vinyl acrylate, nylon, polyester, and mixtures (and/or layers)thereof In a particular embodiment the polymer is polypropylene, whichcan be any polymer having at least 50 wt %, by weight of the polymer, ofpropylene-derived units. In a particular embodiment, the polymer ispolypropylene. The “polypropylene” is a polymer comprising from 98 wt %to 100 wt % propylene-derived units and can be made by any desirableprocess using any desirable catalyst as is known in the art, such as aZiegler-Natta catalyst, a metallocene catalyst, or other single-sitecatalyst, using solution, slurry, high pressure, or gas phase processes.The polypropylenes have a melting point determined by ASTM D3418 of atleast 130° C. or 140° C., or within a range from 130° C. to 180° C. A“highly crystalline” polypropylene is a preferred polypropylene usefulin certain embodiments, and is typically isotactic and comprises 100 wt% propylene-derived units (propylene homopolymer) and has a relativelyhigh melting point of from greater than (greater than or equal to) 140°C. or 145° C. or 150° C. or 155° C. or 160° C. or 165° C. as measured byASTM D3418.

The term “crystalline,” as used herein, characterizes those polymerswhich possess high degrees of inter- and intra-molecular order. Incertain embodiments, the polypropylene has a heat of fusion (H_(f))greater than 60 J/g or 70 J/g or 80 J/g, as determined by DSC analysis.The heat of fusion is dependent on the composition of the polypropylene;the thermal energy for the highest order of polypropylene is estimatedat 189 J/g that is, 100% crystallinity is equal to a heat of fusion of189 J/g. A polypropylene homopolymer will have a higher heat of fusionthan a copolymer or blend of homopolymer and copolymer.

In any case, in certain embodiments, the polypropylene has a melt flowrate (“MFR”, 230° C., 2.16 kg, ASTM D1238) within the range of from 0.1or 0.5 or 1 to 4 or 6 or 8 or 10 or 12 or 16 or 20 g/10 min. Also, inany case, the polypropylene may have a molecular weight distribution(determined by GPC) of from 1.5 or 2.0 or 2.5 to 3.0 or 3.5 or 4.0 or5.0 or 6.0 or 8.0. Suitable grades of polypropylene, and in particular,highly crystalline polypropylenes that are useful in oriented filmsinclude those made by ExxonMobil, LyondellBasell, Total, Borealis, JapanPolypropylene, Mitsui, and other sources.

In a particular embodiment, the film having the coating comprises atleast three layers, wherein a core layer comprises polypropylene, and atleast one skin layer is adhered to the first and second sides of thecore layer. Even more particularly, there may be tie-layers between oneor both skin-core interface. Thus, the final structure may be one ofA/B/C/B/A, wherein “A” is a skin layer, where each layer may be made ofthe same or different materials,

“B” is a tie-layer (each the same or different), and “C” is a corelayer. Desirably, the polyalkylimine condensation product is coated onat least one skin layer. In certain embodiments, the first side of thefilm has ink printed thereon, and the second side has adhesive adheredthereto.

The film can be coated by any suitable means. Preferably, the coating isapplied to a film using a gravure coater, the coating composition havinga solids level within the range of from 0.5 or 1.0 wt % to 4 wt % or 5wt % or 6 wt %. When a primer is present, the primer may be similarlyapplied.

Any one or all of the layers may have certain additives included withthe primary polymer materials used to make the layers. The condensationproduct coating may also comprise similar additives. In a particularembodiment, however, anti-blocking agents are substantially absent fromthe coating. Anti-block agents can be an actual film layer such aspolyethylene, but can also be an additive to a film layer such as silicaor other additive as is known in the art. In any case, when present, thecondensation product coating comprises from 1 wt % or 5 wt % or 10 wt %to 20 wt % or 30 wt % or 40 wt % or 50 wt % anti-block agent. With orwithout the oxidation treatment or anti-blocking agents, in certainembodiments the coefficient of friction of the coated film is less than1 or 0.8 or 0.5 or 0.4.

In any case, other “additives” include compositions such as cavitatingagents (e.g., CaCO₃), opacifying agents, pigments, colorants, slipagents, antioxidants, anti-fog agents, anti-static agents, fillers,moisture barrier additives, gas barrier additives, and combinationsthereof, as discussed in further detail below. Preferably, the totalamount of additives, including cavitating agents, in the first skinlayer ranges from about 0.2 wt % or 0.5 wt % to 2 wt % or 4 wt % or 8 wt% or 10 wt % or 20 wt % or 40 wt %. In certain embodiments, theanti-block is not an additive but is an oxidation treatment of the skinsurface such as a plasma, corona or flame treatment as is known in theart.

Preferably, primers are present in the coated films. Most preferably,the primary component of the primer is the same or similar to thecoating polymer, but with other additives. Most preferably, PAIs areused as primers. In certain embodiments, the primer consists essentiallyof a PAI as described herein.

Throughout the specification, when stating “consisting essentially of”what is meant is that the any other components and/or additives, ifpresent, are present to no more than 1 wt % or 2 wt % or 3 wt % or 5 wt% of the claimed composition.

The coated films described herein have many uses, but are particularlydesirable in labels, such as adhesive labels, especially labels forprinting and attaching to articles of manufacture, and most preferablypressure sensitive labels where printing is required. Most preferably,the inventive films are coated on the side of the film to be printedupon, or “print side” of the film. The usefulness of this isdemonstrated in the following non-limiting examples.

EXAMPLES Example 1 Condensation Polymer Stability at Elevated pH

This example merely distinguishes the physical characteristics of theinventive condensation polymers from polymers described in U.S. Pat. No.6,893,722. That patent disclosed that the polymer therein exists as astable emulsion or solution in water only when the pH is ≦8. PolymerExample A (from the '722 patent, col. 29) was diluted to 10% solids. Anattempt was made to increase the pH of this emulsion by adding ammoniato about 100 mL of the emulsion that was being stirred in a beaker witha Teflon-coated stirring bar. Addition of ammonia to the emulsion causedlocalized coagulation. Before the pH exceeded 7.0, the entire beaker ofcoating had solidified. This result is consistent with a similarcondensation reaction described in the '722 patent with a differentpolymer backbone.

In a separate beaker, a blend containing 100 parts (on a dry basis)Mica™ H760A (from Mica Corporation, M_(w) greater than about 500,000)and 175 parts acetoacetoxyethyl methacrylate (AAEM) diluted to 10%theoretical solids with water was also stirred. The condensationreaction was allowed to go to completion. The initial pH of this blendwas about 6.9. Ammonia was added to the reaction product and the pHincreased to 9.5 without any sign of kick out or coagulation. Thisdemonstrates that the polymers from this invention are stable at pHvalues greater than 8 and, therefore, distinct from the polymers in the'722 patent having the styrenic-containing backbone.

In general, condensation polymers described herein are believed to bemuch easier to formulate than polymers from the '722 patent, because thepH can be increased with bases like ammonia or lowered with acids likeacetic acid. In contrast, it has been shown to be difficult to increasethe pH of polymers from the '722 patent, because of coagulation issues.

Several blends in Example 2 also have pH values above 8 at the end ofreaction without any subsequent pH adjustment. While polymer emulsionsfrom this invention are stable at pH values greater than 8, it is stillwithin the scope of this invention to use coating formulationscontaining condensation polymers that are at pH values below 8.

Example 2 Synthesis of Condensation Polymers

Several condensation polymers were made using polyalkylimines (PAIs)like Mica™ H760A or Epomin™ P1050 (PEI, polyethylene imine from NipponShokubai, M_(W) about 70,000) and a material containing acetoacetatefunctionality (ethyl acetoacetate [EtOAcAc] or acetoacetoxyethylmethacrylate [AAEM] or oxirane functionality (glycidyl methacrylate[GMA]). The blends were prepared by mixing the amino-functional polymerwith water. Once dispersed, the modifier [acetoacetonate(“AcAc”)-functional material or oxirane-functional material] was added.At ≧10% solids, the modifiers were added while the poly-amine wasstirring to minimize precipitation. The following Table 1 summarizes theblends that were prepared:

TABLE 1 PAI Dry Modifier Blend # Type phr Type Phr ARE Solids % pHComments 1 Mica 100 None 0 0 1.5 8.83 Clear, faint yellow; 3.7 cP H760A2 Mica 100 AAEM 25 0.117 1.5 8.18 Clear, amber; 3.5 cP H760A 3 Mica 100AAEM 50 0.233 1.5 7.79 Clear, dark amber; 3.2 cP H760A 4 Mica 100 AAEM75 0.350 1.5 7.54 Clear, brownish; 3.1 cP H760A 5 Mica 100 AAEM 1000.467 1.5 7.32 Clear, amber; 2.9 cP H760A 6 Mica 100 AAEM 125 0.584 1.57.25 Clear, bright yellow; 2.9 cP H760A 7 Mica 100 AAEM 150 0.700 1.57.18 Sl. turbid, bright yellow; H760A 2.9 cP 8 Mica 100 AAEM 175 0.8171.5 7.07 Turbid, bright yellow; H760A 3.2 cP 9 Mica 100 AAEM 200 0.9341.5 7.00 Turbid, bright yellow; H760A 3.0 cP 10 Mica 100 EtOAcAc 250.192 1.5 8.63 Clear, amber H760A 11 Mica 100 EtOAcAc 75 0.576 1.5 8.14Clear, bright yellow H760A 12 Mica 100 EtOAcAc 125 0.961 1.5 7.69 Sl.turbid, yellow H760A 13 Mica 100 EtOAcAc 175 1.34 1.5 7.57 Sl. turbid,yellow H760A 14 Mica 100 AAEM 200 0.934 3 7.64 Turbid, bright yellow;H760A 3.0 cP 15 Mica 100 AAEM 200 0.934 4 7.62 Turbid, bright yellow;H760A 3.0 cP 16 Mica 100 AAEM 100 0.467 3 8.23 Turbid, bright orange;3.4 cP H760A 17 Mica 100 AAEM 100 0.467 4 8.22 Turbid, bright orange;3.6 cP H760A 18 Mica 100 AAEM 100 0.467 10 8.25 Turbid, bright orange;11 cP H760A 19 Mica 100 AAEM 200 0.934 10 7.59 Turbid; bright yellow;sl. H760A grit; 3.6 cP 20 Mica 100 AAEM 200 0.934 15 7.63 Bright yellow;gritty; 3.8 cP H760A 21 Mica 100 AAEM 200 0.934 20 — Gelled in <15minutes. H760A 22 P1050 100 AAEM 500 2.34 6 7.73 Sl. turbid; v. littlecolor 23 P1050 100 AAEM 500 2.34 10 7.49 Sl. turbid; v. little color;4.5 cP 24 P1050 100 EtOAcAc 300 2.30 10 8.73 Clear; v. little color; 5.9cP 25 Mica 100 AAEM 175 1.34 10 7.63 Bright yellow; grit-free; H760A 3.6cP 26 Mica 100 GMA 133 0.936 10 7.37 Clear, amber; 6.3 cP H760A

For purposes of calculating the blending ratios, it was assumed thatMica H760A was 12% solids; Epomin™ P1050 was 50% solids, and the AcAcand glycidyl additives were treated as 100% active. The pH values weremeasured between one and four days after the initial blends were made.For a few selected samples the pH changes versus time were monitored.Generally speaking, the pH stabilized within 24 hours of mixing thecomponents indicating that the condensation reactions were substantiallycomplete within one day.

To simplify comparisons among modifiers having different equivalentweights, the above table normalizes the parts of modifier per hundredparts of the PAI (phr) into the number of amine-reactive equivalents(“ARE”) per hundred parts of PAI. Therefore, for example, when Mica™H760A is the PAI, 200-phr AAEM will functionalize, on a molar basis,about the same number of amine groups as 133-phr GMA. If polyethyleneimine were strictly a linear polymer, then the repeat unit would beabout 45 g/equivalent. Therefore, it would theoretically take 2.22 AREto fully functionalize 100g (100 parts) of a linear PEI molecule. Chainbranching or other chemical modification of the polyalkylimine wouldaffect the amount of amine groups that would be available for reactionwith modifiers described in this invention. While not wanting to bebound by theory, one could anticipate that ≦2.5 AREs would be sufficientto fully functionalize PAIs based on polyethylene imine (allowing for aslight molar excess of the modifier to help increase reaction ratesand/or to increase the equilibrium concentration of the condensationpolymer). Since the exact chemical compositions of commerciallyavailable PAIs are not generally known to those outside the supplyingcompany, suitable blend ratios must be determined empirically for eachPAI type.

Blends 19, 20, and 21 were the only ones that showed any evidence ofgrit formation from the chemical reaction. Other than Blend 21, allsamples were low viscosity at the end and/or in-process. AAEM blends hadvery little odor after the reaction was complete. Blends with EtOAcAc orGMA had more noticeable odors.

Blends 23 and 24 from Example 2 were applied to the print surface ofLabel-Lyte™ 196 LL B2 from ExxonMobil using a lab-scale coater, whichapplied coating directly to the substrate a 200-Quad gravure cylinder atabout 40 feet/min. The coating was dried at 99° C. in an oven that wasabout 4 feet long. Formulations in Table 2 are based on 100 partscondensation polymer. Before applying the twelve topcoats below, thesame line conditions were used to prime the film with a solutioncontaining 0.1% Mica H760A that was adjusted to pH 10 with ammonia. Theestimated coating weight of the primer is about 0.003 g/m². In-linecorona treatment was used to improve the wet out of the primer, but nocorona treatment was used when coatings were applied to primed film.Some topcoat formulations contained colloidal silica (Ludox™ CLP fromGrace Davison), which reduces the tendency of the printable surface tostick to the adhesive-receiving surface on the other side of the film.All the coating formulations also contained 0.5% Hexyl Cellosolve™(Union Carbide) to improve the uniformity of the coating lay down overthe primer.

Printability Tests: A 355.34.PW screen (supplied by Nor-CoteInternational, Inc., Crawfordsville, Ind.) and a squeegee were used tohand apply the black screen ink (UVN-50 Mixing Black screen ink from SunChemical) to a 3-inch by 3-inch patch on the coated surface of a filmsample. After applying the ink, it was cured by passing the printedsample twice under the UV curing lamp in an apparatus built by FusionSystems® at 100 feet per minute. The cured ink was about 7 micronsthick.

To simulate print performance in the first station of a multi-stationprinting press, samples were printed with ink on test surfaces that hadno prior exposure to UV light followed by two passes under the UV lampto cure the ink. This is the “0-Ink-2” curing protocol. Each pass underthe UV lamp typically exposed the sample to an energy equivalent thatwas between 0.09 and 0.12 Joules/cm².

To simulate print performance in one of the latter stations of amulti-station printing press, test surfaces were passed five times underthe UV lamp at 100 feet per minute prior to the application of ink(followed by an additional two passes to cure the ink). This is the“5-Ink-2” curing protocol.

After samples were printed, initial ink adhesion was tested using threestrips of 1-inch wide Scotch™ 600 tape laid across the entire 3×3-inchpatch of cured black screen ink and air bubbles were pressed out byhand. After leaving the tape on the surface for 1 to 2 minutes, eachstrip of tape is rapidly peeled off Samples were rated on the percentageof ink left on the entire 3×3 block after all three pieces of tape havebeen removed. The amount of ink remaining was recorded as the %INK.

Retained ink adhesion after immersion was tested in a similar fashion,but two different tapes were used and the dwell times were a littleshorter. Printed samples were prepared using both curing protocols asdescribed previously. After waiting four to seven days, samples wereimmersed for 24±4 hours in deionized water. After patting the sample drywith a paper towel, three strips of 1-inch wide Scotch 610 were quicklyapplied to cover the entire 3×3 printed surface. After a dwell time ofbetween 10 and 30 seconds, the tape was quickly removed, and then three1-inch strips of Scotch 600 tape were immediately applied to the sameprinted area on the sample. After a dwell time of between 10 and 30seconds, the Scotch 600 tape was quickly peeled off The amount of inkleft after being tested with both tapes was recorded as %INK-W.

After coating, the samples were tested for %INK and %INK-W, as describedin Example 3. The results are shown in Table 2.

TABLE 2 Coating Ludox Coated AcAc Weight CLP % INK: % INK: % INK-W: %INK-W: Sample Type (g/m²) (parts) (0-Ink-2) (5-Ink-2) (0-Ink-2)(5-Ink-2) 2-1 AAEM 0.03 0 100 100 99 30 2-2 AAEM 0.03 30 100 100 99 402-3 AAEM 0.15 0 100 100 99 0 2-4 AAEM 0.15 30 100 100 15 0 2-5 AAEM 0.270 100 100 100 0 2-6 AAEM 0.27 30 100 100 32 0 2-7 EtOAcAc 0.03 0 36 28 00 2-8 EtOAcAc 0.03 30 14 14 0 0 2-9 EtOAcAc 0.15 0 6 44 0 0 2-10 EtOAcAc0.15 30 15 4 0 0 2-11 EtOAcAc 0.27 0 33 4 0 0 2-12 EtOAcAc 0.27 30 8 6 00

While AAEM and EtOAcAc both form enamines with the polyalkylimine,results in Table 2 show that it is preferable for the condensationpolymer to contain ethenic unsaturation (from AAEM in this example) whenradiation-curable printing inks are used. The results also show thatretained ink adhesion after immersion in water (%INK-W) was better whenthe condensation polymer of this invention was applied at a lowercoating weight. Example 3 more completely describes the response ofprintability to changes in coating weight.

Example 3 Inventive and Comparative Example

This example will demonstrate that the embodiments of the polyalkyliminecondensation product provides better print performance at coatingweights that are much lower than taught in U.S. Pat. No. 6,893,722.

In the '722 patent, coating formulations were applied at 5% solids usinga 130-Quad gravure cylinder to the print surface of Label-Lyte 196 LL B2from ExxonMobil Chemical Films Business, which would yield a coatingweight of about 0.19 g/m² after drying at 250° F. These coated filmswere subsequently printed with a black UV-screen ink and evaluated forinitial ink adhesion and adhesion after immersion in water.

Two preferred examples were selected from the '722 patent for thepurposes of comparison with the current invention. From Example 7 (US'722), the coating composition described in Table 3 using Polymer A wasrecreated at 10% solids and applied using essentially the same coaterand line conditions, except that a 200-Quad gravure cylinder was used.After coating a sample at 10% solids, serial dilutions with 0.5%hexyl-cellosolve in deionized water were used to create samples withcoatings at 5%, 2%, 1%, and 0.67% solids so that ink adhesion as afunction of coating weight could be evaluated. Similar sample sets wereprepared using the coating composition described in Example 10 (Table 6,roll 8) of the '722 patent.

A condensation polymer consistent with the present invention (Blend 19in Table 1) was prepared from a mixture of 5128 g Mica H760A (11.7%solids, 100 parts), 1200 g acetoacetoxyethyl methacrylate (AAEM), and11672 g deionized water (for 10% theoretical solids). After completionof the condensation reaction 0.5% Hexyl Cellosolve was added to ensurethat the coating wet the substrate properly. A solution of 0.5% HexylCellosolve was used for making the serial dilutions of this polymer.

Similarly, a condensation polymer consistent with the present invention(Blend 26 in Table 1) was prepared from a mixture of 73.4 g Mica H760A(11.7% solids, 100 parts), 11.4 g (glycidyl methacrylate inhibited with50 ppm hydroquinone monomethyl ether from Sigma-Aldrich, 133 parts), and115.2 g deionized water (for 10% theoretical solids). After completionof the condensation reaction, 0.5% Hexyl Cellosolve and 0.05% Tergitol™15S9 were added to ensure that the coating wet the substrate properly.For this condensation polymer, the addition of Hexyl Cellosolve alonewas insufficient to yield robust wetting properties. A solution of 0.5%Hexyl Cellosolve and 0.05% Tergitol 15S9 was used for making the serialdilutions of this condensation polymer.

The compositions were coated on films. Coating weights were calculatedbased on the weight of wet coating used to cover about 10 m² of surfacearea (the web was 12.7 cm wide). The amount of dry coating wascalculated from the percent coating solids times the amount of wetcoating that was consumed. Sample length was determined by multiplyingthe line speed (determined with a tachometer from Extech Instruments)times the length of time that the coating station was engaged.

The black UV-screen ink used in the '722 patent was no longer available;

therefore, we selected UVN-50 Mixing Black screen ink from Sun Chemicalto evaluate ink adhesion using the following printability testsdescribed above in Example 2. For %INK, FIG. 1 shows results for the0-Ink-2 curing protocol versus coating weight, and FIG. 2 shows resultsfor the 5-Ink-2 curing protocol. For %INK-W, FIG. 3 shows results forthe 0-Ink-2 curing protocol versus coating weight, and FIG. 4 showsresults for the 5-Ink-2 curing protocol.

With every curing protocol and test condition, the present coatingcomposition yields good results with coating weights below 0.3 or 0.2g/m², and most preferably below 0.1 g/m² and varying degrees of adhesionloss above 0.1 g/m². Just the opposite is true for examples from the'722 patent: Most results for coating weights below 0.1 g/m² were poor(less than 90%) and excellent above 0.1 g/m².

Example 3 Primers and Anti-Block

High-performance label films in the industry usually have one sidedesignated as the printable surface and the opposite side is designatedas the adhesive-receiving surface (examples: from ExxonMobil: Label-Lyte50LL539, Label-Lyte 50LL534 II; Rayoface™ CPA). Occasionally, roll stocklaminators will apply the pressure-sensitive adhesive to the wrong sideof the film due to improper labeling of the input film or improperlymounting the roll on the line. The result is wasted material that isunsuitable for printing.

It would be desirable to have a label facestock that is capable ofreceiving adhesive or ink (especially radiation-cured inks) to eitherside of the label stock. This is technically challenging, for eachsurface must be capable of adhering a broad range of adhesives andprinting inks while maintaining a low affinity between the opposingsides of a two-side coated label facestock. This is very challengingeven if different coatings are used on opposing sides. The examples willshow that condensation polymer technology can create such structureswith symmetrically coated films.

While it is possible to use primers well known in the art (for example,Epoxy per Steiner et al., U.S. Pat. No. 4,214,039, Epomin™ P1050,Lupasol™ WF, Lupasol™ P, Mica™ H760A, Aquaforte™ 108W, etc.) exampleswill show that condensation polymers of this invention also makeexcellent primers for the formulated topcoat based on the condensationpolymer. Moreover, while Mica H760A offers excellent properties whenused as a primer, the structures tend to have a noticeable yellow color,which some end users might find undesirable. In contrast, similarstructures prepared with a condensation polymer have very little colorat all (See Example 4).

Example 3-1

(Print face as taught in U.S. Pat. No. 6,893,722; adhesive-receivingaccording to US 2007/0248810A1). Using a custom-built pilot-scale coaterhaving a station to apply and dry a primer via an offset roll and atopcoat station that applies coating via reverse direct gravure, astructure was prepared in which a block-resistant adhesive-receivingcoating was applied at 0.30 g/m² to one side of primed Label-Lyte 196 LLB2 from ExxonMobil that comprised 100 parts MichemPrime™ 4983.15 (fromMichelman, Inc.), 70 parts NeoCryl™ XK90 (from DSM NeoResins), Ludox™AS40 (from Grace Davison), 15.6 parts AZCote™ 5800M (from Akzo Nobel),MichemLube™ 215 (from Michelman, Inc.), Multifex-MM™ (SpecialtyMinerals, Inc.), 0.3 parts Tergitol™ 15S9 (Union Carbide), and 5 ppmFoamaster™ 223 (Cognis). The topcoat was dried at 175° F.

The primer beneath the adhesive-receiving coating was Mica H760A appliedat a thickness that yielded an optical density of between 0.060 and0.065 when measured at 510 nm with a Radiachromic Reader (Far WestTechnology, Inc.) after a piece of Label-Lyte 196 LL B2 coated only withthe primer was immersed for 30 seconds in a 0.83 g/L methanolic solutionof the potassium salt of ethyl eosin (Sigma-Aldrich) that was rinsedwith water and patted dry with a tissue. The primer was dried at 175° F.Line speed was set at 175 fpm and the film was treated with a bare-rolltreater (from Pillar) with a power setting of 1.0 kW.

After preparing a one-side coated roll that was about 2000 feet long and26 inches wide, the film was sent through the coater again with the sameline conditions and primer so that the printable coating could beapplied to the other side of the film.

The primer station contained a 200-Quad gravure cylinder thattransferred the coating to an offset roll, which applied the coating tothe film. The topcoat station was equipped with a 330-1pi ceramicgravure cylinder used as a kiss coater to apply the coating to the filmwhile rotating at the same speed but in the direction opposite to thatof the moving web.

The printable coating comprised 100 parts R1117 XL (Owensboro SpecialtyPolymers, LLC), 30 parts Ludox CLP, 5 parts acetoacetoxyethylmethacrylate (Sigma-Aldrich), 1 part MichemEmulsion™ 09730 (Michelman,Inc.), and 0.5 parts Tospearl™ 120 (Momentive Performance MaterialsJapan LLC). The coating weight for the printable surface was about 0.13g/m² and was applied at 12% solids. The coating weights for this examplewere determined by weighing about 0.023 m² of coated film before andafter the coatings were removed by hand extraction with methyl ethylketone.

Four days after the two-side coated structure was prepared, the 26-wideroll was slit into smaller rolls on a Dusenbery ribbon slitter. To lookfor blocking problems that might occur during shipment to tropicallocations, a slit roll that was 4¾ inches wide and 1500 to 1700 feetlong on a 3½-inch outside diameter (“OD”) cardboard core was placed intoa conditioning cabinet (Model 518 from Electro-tech System, Inc.) set at50° C./50% RH for one week. After removing the roll from theconditioning cabinet, a small slab of film was taken from the outerportion of the roll for printing tests (see table), and the remainder ofthe roll was moved to ambient storage conditions. Six days later, anattempt was made to unwind the roll at about 600 feet/min on theDusenbery ribbon slitter.

After conditioning, this roll had very little color. When the roll wasunwound, continuous hissing was heard, then near the core the web broke.It was observed that if the printable surface of this example wereapplied to both sides of the structure, it would not be possible tounwind the film at all after a week of conditioning in a tropicalenvironment.

Example 3-2

(Example demonstrating the invention on a clear substrate) A two-sidedcoated roll was prepared, slit, and conditioned as described in Example3-1 with the following differences. Mica H760A was applied in thepre-coat station such that the optical density at 510 nm after stainingthe dried primer (without a topcoat) with eosin dye was between 0.103and 0.111.

Unlike Example 3-1, the same topcoat (applied over the top of the driedprimer) was used on both sides of the film, which comprised 100 parts ofthe Mica/AAEM condensation polymer described in Table 1 (Blend 19) and100 parts Ludox CLP. The calculated average coating weight (based on thetotal amount of topcoat used after coating both sides) was 0.0307 g/m²and was applied at 2% solids. The hand-extraction method used in Example3-1 is not practical for such low coating weights.

After conditioning, this roll was noticeably more yellow than the rollin Example 3-1; however, the difference was not discernable to the eyewhen looking at only a few sheets. This roll unwound with less noisethan Example 3-1. The web also broke very near the core, but closerexamination revealed a coating defect caused by a wrinkle in the webthat created a spot on the very edge of the slit roll in which theprimer was not covered by the topcoat.

Example 3-3

(Example demonstrating the invention on a clear substrate) A two-sidedcoated roll was prepared as described in Example 3-2, except that thetopcoat was applied at 3% solids to achieve a calculated coating weightof 0.0459 g/m².

This sample was slightly yellower than Example 3-2. Initially thissample showed no hissing when it was unwound after conditioning for aweek at 50° C./50% RH. Toward the middle of the roll and down to thecore, very light hissing was heard periodically (perhaps due to slightvariations in the coating weight). This conditioned roll was unwound tothe core without tearing.

Example 3-4

(Example showing the current invention on an opaque substrate) Atwo-side coated roll was prepared, slit, and conditioned as described inExample 3-2 with the following differences. Mica H760A was applied inthe pre-coat station such that the optical density at 510 nm afterstaining the dried primer (without a topcoat) with eosin dye was between0.146 and 0.158. The oven temperature for the primer was about 70° C.

After determining the coating weight for the primer on clear film, theadhesive-receiving surface was prepared by coating Label-Lyte™ 160LL302, which is a cavitated white opaque substrate with the primer and atopcoat comprising 100-phr of a condensation polymer (Blend 19, Table1), 100-phr Ludox CLP, and 15-phr barium sulfate (Blanc Fixe Micro Plus™from Sachtleben, Duisburg, Germany) at a dry coating weight of about0.03 g/m². The adhesive-receiving coating was dried at 88° C. Note thesimilarity between this adhesive-receiving coating and the printablecoating in for Example 3-2. The barium sulfate enhances blockresistance, but it would undesirably increase the haze of a clear film.Conceptually, this coating could have been applied to both sides of thecavitated substrate, and printability would have been acceptable on bothsides.

The print-face coating was applied over the same primer on the oppositeof the film in a second pass through the coater. The print-face coatingwas different than the coating used on the adhesive-receiving surface:100-phr condensation polymer (Blend 19, Table 1), 30-phr Ludox CLP,15-phr Blanc Fixe Micro Plus™ at a dry coating weight of approximately0.023 g/m². The print-face coating was also dried at 88° C.

This sample had a very white appearance (not yellow). After conditioninga narrow slit roll for a week at 50° C./50% RH, it was possible tounwind this roll down to the core without tearing and only slighthissing near the core.

The following table shows ink adhesion (initially and after immersion inwater) determined by the methods described in the comparative example.

TABLE 3 Ink Adhesion for Ink Adhesion for Samples Conditioned AmbientSamples at 50° C./50% RH for One Week % INK % INK-W % INK % INK-W Sample0-Ink-2 5-Ink-2 0-Ink-2 5-Ink-2 0-Ink-2 5-Ink-2 0-Ink-2 5-Ink-2 3-1 100100 58 94 36 43 34 8 3-2 100 100 99 88 100 100 100 25 3-3 100 97 100 66100 100 100 99 3-4 100 100 100 99 100 100 100 100

This example shows that coatings of the present invention formulated forblock resistance yield excellent printability, even after exposure toharsh conditions that might be experienced during shipping to a tropicalclimate. Moreover, results for the conditioned samples are superior tothe disclosures in the '722 patent. Furthermore, excellent printabilityis available on both sides of the structure, and reduces the risk of aroll-stock laminator having to dispose of film in which thepressure-sensitive adhesive was applied to the wrong side of the film.

Ink applied to the adhesive-receiving side of Example 3-1 would yieldessentially 0% adhesion for all the above tests and conditions.Moreover, attempts to enhance block resistance of Example 3-1 byincreasing the amount of colloidal silica in the printable coatingresulted in further degradation of the print performance, especiallyafter immersion in water.

Example 4 Primer Layer

This example shows that condensation polymers of the present inventioncan be used in the primer layer and the topcoat layer at the same time.One-sided coated samples were prepared on a small, single-stationcoater, as described in Example 2, except that two passes were requiredfor each sample. In the first pass, the primer was applied to theadhesive side of Label-Lyte 196 LL B2 from ExxonMobil with the coronatreater set at about 50% of its power output. As before, a 200-Quadcylinder was used to apply the coatings directly to the film samples(the gravure cylinder was moving the same direction as the web). Afterdrying at 80° C., the roll was sent through the coater again with thetopcoat being applied over the dried primer. No additional coronatreatment was used on the second pass.

The final structure had the primer and topcoat on the coated side, withthe uncoated print surface of Label-Lyte 196 LL B2 on the opposingsurface, which has a surface energy that is greater than 40 dynes (asdetermined with a Poly Treat Check Pen™ from Independent Ink Inc.). Someadhesives anchor adequately to an uncoated surface that has been coronaor flame treated. In this example, one-sided coated samples were pressedagainst the untreated coated surface (that is, in to out [I/O]) for onehour at an effective pressure of 750 psi (7500 lbs pressure applied to10 in²) at 60° C. The blocking force was measured using a 90° T-peeltest on an Instron. The same samples were also paired so that the coatedsurfaces were in contact with one another (that is, out to out [O/O])and tested in the same way to estimate blocking tendencies of conceptualsymmetrically coated structures.

All samples in this series had the same printable topcoat comprising 100parts of the condensation polymer described in the comparative example,100 parts Ludox™ CLP, 9.4 parts Tergitol™ 15S9 (0.05% of the total wetcoating), and deionized water to yield a total solids content of 1.1%.The approximate coating weight was 0.031 g/m² after drying. Colloidalsilica (Ludox™ CLP) is included in the topcoat formulation to helpmitigate blocking to the opposite side of the film.

All primers in this series contained various concentrations of thecondensation polymer described in the comparative example combined with0.025% Tergitol 15S9 and 0.25% Hexyl Cellosolve in the wet coating tofacilitate wetting of the substrate. Coating solids were set at 0.33%,0.50%, 0.67%, and 1.0% solids to achieve the coating weights shown inFIG. 5. It should be noted that when primers based on the condensationpolymers were used, the coated films had much less color than thestructures described in Example 3 that had Mica H760A as the primer.Including colloidal silica in the primer layer tends to diminish %INK-W;therefore, primers preferably do not contain significant amounts ofcolloidal silica or other materials that might compromise waterresistance.

FIG. 5 shows that increasing the thickness of the primer increased theundesirable blocking tendencies of the coated structure whether thesurface opposite the print face is coated or just treated. Based onthese results, one can conclude that a desirable coating weight for theprimer is less than 0.020 g/m² and more preferably less than 0.015 g/m².(These thicknesses apply to primers, typically not to topcoats.)Moreover, blocking resistance is more robust if coatings of thisinvention are used on both sides of the film rather than just coatingone side and treating the other (without coating). Nevertheless, usefulone- or two-sided structures could be prepared with the coatings of thisinvention if the primer thickness was properly controlled.

Example 5 Other Polyethyleneimines

This example shows that one can use other polyethyleneimine polymers toprepare useful condensation polymers. Two condensation polymers wereprepared at 10% theoretical solids by mixing for greater than 24 hourswith a Teflon coated magnetic stirring bar: Polymer 4A (of Table 4)comprising 57.0 g Mica H760A (11.7% solids, 100 parts), 13.33 gacetoacetoxyethyl methacrylate (200 parts), and 129.7 g deionized waterand Polymer 4B comprising 6.7 g Epomin P1050 (50% solids, 100 parts,from Nippon Shokubai), 16.67 g acetoacetoxyethyl methacrylate (500parts), and 176.7 g deionized water. Polymer 4A was a yellowish,somewhat translucent emulsion and Polymer 4B was an essentiallycolorless (whitish), translucent emulsion.

The emulsions were blended into the following coating formulations andcoated on Label-Lyte 196 LL B2 from ExxonMobil as described in Example4. All formulations contained 0.25% Hexyl Cellosolve to facilitatewetting of the substrate. The amount of Ludox CLP is based on 100 partsof the respective condensation polymer used in the formulation. Inkadhesion (%INK and %INK-W) were determined as described previously.

TABLE 4 % INK % INK-W Parts Coating Coating 0- 5- 0- 5- Poly LudoxSolids Weight Ink- Ink- Ink- Ink- Sample Type CLP (%) (g/m²) 2 2 2 2 5-14A 100 0.67 0.0186 77 56 5 3 5-2 4B 100 0.67 0.0186 99.5 73 11 4 5-3 4A50 1.00 0.0279 100 100 53 3 5-4 4B 50 1.00 0.0279 100 100 60 9

The above results show less than optimal results for retained inkadhesion after printed samples were immersed in water, because no primerwas present beneath the printable topcoat. These results also show thatcondensation polymers based on Epomin P1050 compare favorably in printperformance to those created from Mica H760A.

Besides having less color, coatings based on Polymer 4B have the addedadvantage of having lower surface resistivity, which would enhance theability of the coated film to dissipate static. Surface resistivity wasmeasured at 50% RH, 24° C. using a Keithley Model 8008 Resistivity TestFixture attached to a Keithley Model 487 picoammeter/voltage source inwhich the applied voltage was set at 10.000 volts. The results appear inthe following Table 5.

TABLE 5 Sample Polymer Type Surface Resistivity (Log Ω/□) 5-1 4A 13.55-2 4B 13.0 5-3 4A 13.2 5-4 4B 12.5

Example 6 Printable Structures Made from VOC-Free Condensation PolymersFormulated to Lower Coefficient of Friction and to Enhance ScuffResistance

To aid in dispensing or stacking label face stocks, it is advantageousto control the coefficient of friction (COF) on the outside surface ofthe label. To maintain an attractive appearance, it is also desirable tohave a coated surface that is resistant to scratching and scuffing andsolvents such as isopropyl alcohol. Using waxes and particulates incoating formulations to accomplish this in addition to block resistanceis well known in the art. It is far more difficult, however, to create ascuff-resistant and chemically-resistant structure that is stillreceptive to print inks.

Primed samples were created for this example as described in Example 4.The primer for all three topcoats described in this example contained100 parts of the condensation polymer made in Blend 26 (Table 1)formulated with 15 parts Tergitol 15S9 and diluted to a total solidscontent of 0.33%. This formulation is substantially free of VOCs.

Topcoat 6-1: This VOC-free coating comprised 100 parts of Blend 26(Mica-GMA, Table 1), 100 parts colloidal silica (Ludox CLP), 10 partsSurfynol 440 (Air Products, Allentown, Pa.), and diluted with deionizedwater to a total solids content of 1.1%. This material was applied overthe primed film and dried as described in Example 4.

Topcoat 6-2: This VOC-free coating comprised 100 parts of Blend 26, 100parts oxidized high-density polyethylene (MichemEmulsion 91240G.E fromMichelman, Inc., Aubange, Belgium), 10 parts Tergitol 15S9, and dilutedwith deionized water to 1.1% solids.

Topcoat 6-3: This VOC-free coating contained 100 parts of Blend 19(Mica-AAEM, Table 1), 100 parts oxidized HDPE (MichemEmulsion 91240G.E),10 parts Tergitol 15S9, and diluted with deionized water to 1.1% solids.

Kinetic COF was measured for each sample tested against itself (coatedsurface to coated surface) using a slip/peel tester equipped with a 200g sled (Model #32-06 from Testing Machines, Inc., Amityville, N.Y.).

Twenty one-way strokes with the smooth edge of a nickel were made byhand to scuff a 2-inch by 2-inch square on the coated samples. Hazevalues were measured in scuffed and unscuffed areas of the same samplewith a Byk-Gardner Haze-gard Plus. Table 6 shows the results:

TABLE 6 Amine- Anti- Ki- % Haze % Haze Top- Reactive Wetting block neticbefore after coat Modifier Aid Additive COF Scuffing Scuffing 6-1 GMASurfynol Colloidal 0.496 2.82 7.38 440 Silica 6-2 GMA Tergitol Oxidized0.160 3.04 3.50 15S9 HDPE 6-3 AAEM Tergitol Oxidized 0.194 3.02 2.9615S9 HDPE

Table 6 shows that oxidized HDPE is preferable to colloidal silica forimproving scuff resistance. One can also see that changing the chemicalnature of the amine-reactive modifying agent can also have anappreciable impact on scuff resistance. It is not obvious why AAEMshould be preferred over GMA. As shown in Table 1, the ARE values wereessentially the same for Blend 19 and Blend 26 and the same PAI (MicaH760A) was used in both blends. All three coated films were judged to bechemically resistant after rubbing the coated surfaces with an alcoholswab saturated with 70% isopropyl alcohol made by Becton DickinsonConsumer Products, Franklin Lakes, N.J. Haze is tested per ASTM D 1003.

Coated samples were printed by taping individual sheets to a continuousweb that was being printed at 150 feet/minute on a Roto-8-1 printingpress that was set up in the following way:

Station 1: Not in use

Station 2: Contained Pharmaflex Black UV-flexo ink from Water InkTechnologies applied with a 1400 1pi anilox roll that yielded a 1.21 inkdensity.

Station 3: Not in use

Station 4: Not in use

Station 5: Contained Pharmaflex Cyan UV-flexo ink from Water InkTechnologies applied with a 1400 1pi anilox roll that yielded a 1.19 inkdensity.

Station 6: Contained Pharmaflex Magenta UV-flexo ink from Water InkTechnologies applied with a 1400 1pi anilox roll that yielded a 1.42 inkdensity.

Station 7: Contained Pharmaflex Yellow UV-flexo ink from Water InkTechnologies applied with a 1400 1pi anilox roll that yielded a 0.95 inkdensity.

Station 8: Not in use

%INK and %INK-W were measured for all samples. For magenta, cyan, andyellow, all values were 100%. For the black ink, all values were ≧99%,which shows that condensation polymers from this invention can beformulated with low COF and improved scuff resistance with compromisingprintability.

Example 7 Low Molecular Weight PAI-Based Coating

Example 7 demonstrates the advantages of lower molecular weight PAIs.

The following Table 7 shows the formulations for PAI condensationpolymers prepared at 10% theoretical solids having different molecularweights.

TABLE 7 PAI types, cross-linked and non-cross-linked Polymer PAI TypePAI M_(w) PAI (parts) AAEM (parts) PETA (parts) 7-CP1 Epomin 70,000 100440 0 P1050 7-CP2 Epomin 70,000 100 440 11 P1050 7-CP3 Lupasol P 750,000100 440 0 7-CP4 Lupasol P 750,000 100 440 11

An emulsion of each commercial polymer in Table 7 was prepared bydissolving the particular grade of poly(ethyleneimine) completely indeionized water. Epomin P1050 was purchased from Nippon Shokubai, andLupasol P was purchased from BASF. The weight average molecular weightsin Table 7 are in “amu”. Once dissolved, AAEM was added while the PEIsolution was being stirred. In some cases (7-CP2 and 7-CP4), PETA(pentaerythritol triacrylate) was added as a cross-linker about one hourafter the AAEM was added. The mixtures were stirred for at least 24hours after the AAEM was added.

Using the polymers in Table 7, coatings were formulated and applied tofilms as in Example 3 to create symmetrically coated clear structures onthe 26-inch wide coater, followed by slitting, and conditioning in atropical environment, as described in Example 3. As indicated in theTable 8, two different primer formulations were used to create samplesfor this example that were based on the condensation polymers describedabove.

TABLE 8 Primer compositions Tergitol 15S9 Primer Solids Primer ID PAIType PAI (parts) (parts) (%) 7-PC-A 7-CP1 100 15 0.33 7-PC-B 7-CP3 10015 0.33

Topcoats were applied to the primed surface using a 550-1 pi ceramicgravure cylinder using a combination of dilution and gravure-speedadjustments to achieve the indicated coating weights. All coatingscontained 0.03% Tergitol 15S9 to ensure that the topcoat completely wetout the primed surface. The resulting coated films are summarized inTable 9.

TABLE 9 Coated Films Gravure Coating ME91240G.E TC % Speed Weight RollPrimer PAI Type PAI (parts) (parts) Solids (fpm) (g/m²) 7-1 7-PC-A 7-CP1100 100 3.5 −175 0.0353 7-2 7-PC-A 7-CP1 100 100 3.0 −175 0.0276 7-37-PC-A 7-CP2 100 50 3.5 −175 0.0377 7-4 7-PC-A 7-CP2 100 50 3.0 −1750.0293 7-5 7-PC-B 7-CP3 100 100 3.5 −175 0.0388 7-6 7-PC-B 7-CP3 100 1003.0 −175 0.0290 7-7 7-PC-B 7-CP4 100 50 3.5 −310 0.0301 7-8 7-PC-B 7-CP4100 50 3.0 −310 0.0225

Blocking tendencies of the coated films were evaluated in two ways. Theone-hour test is quantitative. Opposite surfaces of the symmetricallycoated samples were pressed together in a Carver Press for one hour withan effective pressure on the blocked samples of 750 psi at a temperatureof 60° C. After removing the pressure, the samples were mounted in anInstron and peeled at 5-inches/min with the samples being held at ˜90°to the peel direction. The average peel force is recorded in grams/inch.

The second blocking method is qualitative, and is described in Example3. In this case the slit rolls were conditioned for a full week at 50°C./50% RH before being unwound on the Dusenbery ribbon slitter at about550 feet/min. An acceptable result for the in-roll blocking test is tohave the sample unwind all the way down to the core without tearing orwithout marring the appearance of the print surface, which usuallyoccurs in the form of high or uneven haze.

The quantitative blocking results from the 1-hour blocking test in Table10 show how the blocking values changed as a function of molecularweight variations in the PAI polymer and to changes in the level ofcross-linker. The mean (of four trials) of the blocking value (g/inch,for 1 hr at 750 lbs/in²) is about 11 g/inch for films having inventivecoating made from PAI having an M_(W) of 70,000 amu (this averageincludes samples with and without cross-linker), and the value is about13.5 g/inch for films with inventive coatings made from PAI having anaverage M_(W) of 750,000 amu (also with and without cross-linker).Therefore, the main effect of increasing the molecular weight of the PAIwas undesirable (increased blocking tendencies), regardless of whetheror not a cross-linker was used. Likewise, the mean (of four trials) ofthe blocking value for cross-linked coatings on films was about 15g/inch (which includes PAIs of high and low molecular weight), and wasonly about 8.5 for non-cross-linked coated films (again, this averageincludes PAIs with high and low molecular weight). Therefore, increasingthe molecular weight by cross-linking, regardless of the initialmolecular weight of the PAI, yielded poorer (increased) blocking values.Typically one would expect that higher molecular weight would improveblock resistance. In summary, these data demonstrate the unexpectedresult that higher molecular weight, achieved either by polymerizationor cross-linking, increased the blocking tendencies of the PAIcondensation polymer.

Trends consistent with the above quantitative results were seen in thequalitative test, but the qualitative test gives a better idea of thepractical importance of the above trends. The following Table 10 showsthat with the proper molecular weight, symmetrically coated rolls canunwind acceptably, even after exposure to severe tropical conditions.The “XL” in the first column means that the PAI has been cross-linked asidentified above in Table 7. However, if the molecular weight is toohigh, the unwinding properties become unacceptable. These resultssuggest that the preferred molecular weight for poly(ethyleneimine) usedto make the condensation polymers disclosed in this invention is lessthan 100,000 amu. Since the condensation reaction presumably increasesthe molecular weight by the amount of the co-reactant used, then thepreferred molecular weight for the condensation polymer is probably lessthan 600,000 amu if the PAI is poly(ethyleneimine) and theamine-reactive, ethenically unsaturated modifying agent is AAEM.

TABLE 10 Blocking studies for low molecular weight PAI 1-hr In-rollBlocking Blocking In-roll Blocking Roll ID PAI M_(w) (g/in) (Pass/Fail)Comments 7-1 70,000 6.9 Pass Unwound with very light hissing near thecore. Film appearance at core was uniform. 7-2 70,000 7.5 Pass Unwoundmuch like 7-1. 7-3 (XL) 70,000 14.3 Fail By mid-roll, film appearancewas not uniform. Unwind noise was loud near core and the web brokebefore it could be completely unwound. 7-4 (XL) 70,000 15.1 Fail Unwoundmuch like 7-3. 7-5 750,000 13.0 Fail Completely blocked; roll could notbe unwound at all. 7-6 750,000 11.7 Fail Unwound much like 7-3. 7-7 (XL)750,000 14.1 Fail Roll tore mid-way through roll. 7-8 (XL) 750,000 15.2Fail Unwound much like 7-3.

Having described the various features of the condensation product,polymer, and films having such coating thereon, provided herein innumbered embodiments is:

1. A composition comprising (or consisting essentially of, or consistingof) the condensation product of a polyalkylimine and one or moreamine-reactive molecules comprising (or selected from the groupconsisting of) at least one of:

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

or (and)

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

where Y is halogen or a three-membered oxirane ring; R^(a) and R^(b) arethe same or different and selected from the group consisting of H and C₁to C₆ alkyl; R^(c) is selected from the group consisting of O and CX₂;each X can be the same or different and is selected from the groupconsisting of H, hydroxyl, halogen, and any organic radical containingat least one carbon atom, wherein each R^(d) can be the same ordifferent; A is selected from the group consisting of O and NR^(d);CR^(d) and CR^(d) ₂ can each be a separate moiety or a portion of acyclic structure; j, k, and m are integers ranging from 0 to 6,inclusive; q is an integer ranging from 1 to 6, inclusive; and p is aninteger ranging from 0 to 30, inclusive.

2. The composition of embodiment 1, wherein R^(c) is oxygen (O); R^(a)and R^(b) is methyl or H; X and R^(d) is hydrogen (H); j is 1; k is 0; qis 2; p is 1; and A is oxygen (O).

3. The composition of embodiments 1 or 2, wherein Y is a three-memberedoxirane ring (CH₂(O)CH₂); m is 1; p is 0; A is oxygen (O); R^(b) ismethyl (CH₃); and X is hydrogen (H).

4. The composition of any one of the previous embodiments, wherein from0.1 or 0.2 to 0.6 or 0.8 or 1.0 or 1.1 or 1.2 or 2.0 or 2.5 or 3.0amine-reactive equivalents (“ARE”) is combined with the polyalkylimine.

5. The composition of any one of the previous embodiments, wherein theproduct is isolated from an aqueous diluent in solution at a pH of atleast 8.

6. The composition of any one of the previous embodiments, wherein theamine-reactive molecule is selected from the group consisting ofacetoacetoxyethyl methacrylate, methyl acetoacetonate, ethylacetoacetonate, glycidyl methacrylate, methyl acrylate, acrylamide,acrylonitrile, 1,6-hexanediol diacrylate, 2-hydroxyethyl acrylate,trimethylpropane triacrylate, pentaerythritol triacrylate, and mixturesthereof.

7. The composition of any one of the previous embodiments, wherein thepolyalkylimine comprises C₂ to C₁₀ alkyl or alkenyl-derived units.

8. The composition of any one of the previous embodiments, wherein thepolyalkylimine consists of C₂ to C₁₀ alkyl or alkenyl-derived units, andimine-derived units.

9. The composition of any one of the previous embodiments, wherein thepolyalkylimine is selected from the group consisting ofpolyethyleneimine, polypropyleneimine, polypropyl-co-ethyleneimine, andmixtures thereof.

10. The composition of any one of the previous embodiments, whereinstyrenic moieties are absent from the polyalkylimine.

11. The composition of any one of the previous embodiments, wherein thepolyalkylimine has a weight average molecular weight of from 3,000 or5,000 or 10,000 or 20,000 or 40,000 to 80,000 or 100,000 or 150,000 or200,000 or 300,000 or 500,000 or 1,000,000 or 2,000,000 amu.

12. The composition of any one of the previous embodiments, wherein thecomposition is a suspension having a solids content within the range offrom 0.1% or 0.5% or 1% to 3% or 4% or 5% or 8% or 10% or 30% or 50% or60%, by weight of the coating.

13. A film comprising at least one polymer layer having a first andsecond side, further comprising the coating of any of the previousembodiments on at least the first side, wherein the coating is thecondensation product of a polyalkylimine and one or more amine-reactivemolecules selected from the group consisting of at least one of:

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

and

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

where Y is a halogen or a three-membered oxirane ring; R^(a) and R^(b)are the same or different and selected from the group consisting of Hand C₁ to C₆ alkyl; R^(c) is selected from the group consisting of O andCX₂; each X can be the same or different and is selected from the groupconsisting of H, hydroxyl, halogen, and any organic radical containingat least one carbon atom, wherein each R^(d) can be the same ordifferent; A is selected from the group consisting of O and NR^(d);CR^(d) and CR^(d) ₂ can each be a separate moiety or a portion of acyclic structure; j, k, and m are integers ranging from 0 to 6,inclusive; q is an integer ranging from 1 to 6, inclusive; and p is aninteger ranging from 0 to 30, inclusive.

14. The film of embodiment 13, wherein the first, second or both sidesof the film are coated with the polyalkylimine condensation product.

15. The film of any one of embodiments 13-14, wherein the film is amulti-layered film having outside surfaces on both sides of the film,wherein both of the outside surfaces are coated with the polyalkyliminecondensation product.

16. The film of any one of embodiments 13-15, wherein anti-blockingagents are substantially absent from the coating.

17. The film of any one of embodiments 13-16, wherein the first side ofthe film has ink printed thereon, and the second side has adhesiveadhered thereto.

18. The film of any one of embodiments 13-17, wherein the polymer isselected from the group consisting of polyethylene, polypropylene,ethylene vinyl acrylate, nylon, polyester, and mixtures thereof.

19. The film of embodiment 18, wherein the polymer is polypropylene.

20. The film of any one of embodiment 19, wherein the film comprises atleast three layers, wherein a core layer comprises polypropylene, and atleast one skin layer is adhered to the first and second sides of thecore layer.

21. The film of any one of embodiments 19-20, wherein the polyalkyliminecondensation product is coated on at least one skin layer.

22. The film of any one of the embodiments 19-21, further comprising aprimer layer.

23. The composition of any one of the preceding numbered embodiments,wherein the composition is free of volatile organic compounds.

24. A method of making the film of any one of the preceding embodimentscomprising (or consisting essentially of, or most preferably, consistingof),

(a) combining in an aqueous medium a polyalkylimine and one or moreamine-reactive molecules selected from the group comprising (orconsisting of) at least one of:

R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

and

Y—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂

-   -   where Y is halogen or a three-membered oxirane ring; R^(a) and        R^(b) are the same or different and selected from the group        consisting of H and C₁ to C₆ alkyl; R^(c) is selected from the        group consisting of O and CX₂; each X can be the same or        different and is selected from the group consisting of H,        hydroxyl, halogen, and any organic radical containing at least        one carbon atom, wherein each R^(d) can be the same or        different; A is selected from the group consisting of O and        NR^(d); CR^(d) and CR^(d) ₂ can each be a separate moiety or a        portion of a cyclic structure; j, k, and m are integers ranging        from 0 to 6, inclusive; q is an integer ranging from 1 to 6,        inclusive; and p is an integer ranging from 0 to 30, inclusive;        and

(b) applying the reaction product, without separation or purification,to at least one surface of a film.

25. Also provided is the use of the composition of any one of theprevious numbered embodiments as a coating on a printable film layer fora pressure sensitive label.

26. Also provided is the use of the film of any one of the previousnumbered embodiments in a pressure sensitive label.

1. A film comprising at least one polymer layer having a first andsecond side, further comprising a coating on at least the first side,wherein the coating is the condensation product of a polyalkylimine andone or more amine-reactive molecules comprising at least one of:R^(c)═C(R^(a))—(CX₂)_(j)—C(O)—(CX₂)_(k)—(O—[CR^(d)₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂ andY—(CX₂)_(m)—(O—[CR^(d) ₂]_(q))_(p)-A-C(O)—C(R^(b))═CX₂ where Y ishalogen or a three-membered oxirane ring; R^(a) and R^(b) are the sameor different and are H or a C₁ to C₆ alkyl; R^(c) is O or CX₂; each Xcan be the same or different and is H, hydroxyl, halogen, or any organicradical containing at least one carbon atom, wherein each R^(d) can bethe same or different; A is O or NR^(d); CR^(d) and CR^(d) ₂ can each bea separate moiety or a portion of a cyclic structure; j, k, and m areintegers ranging from 0 to 6, inclusive; q is an integer ranging from 1to 6, inclusive; and p is an integer ranging from 0 to 30, inclusive. 2.The film of claim 1, wherein the first and second sides of the film arecoated with the polyalkylimine condensation product.
 3. The film ofclaim 1, wherein the film is a multi-layered film having outsidesurfaces on both sides of the film, wherein both of the outside surfacesare coated with the polyalkylimine condensation product.
 4. The film ofclaim 1, wherein anti-blocking agents are substantially absent from thecoating.
 5. The film of claim 1, wherein the first side of the film hasink printed thereon, and the second side has adhesive adhered thereto.6. The film of claim 1, wherein the polymer is at least one ofpolyethylene, polypropylene, ethylene vinyl acrylate, nylon, polyester,or mixtures thereof.
 7. The film of claim 6, wherein the film comprisesat least three layers, wherein a core layer comprises polypropylene, andat least one skin layer is adhered to the first and second sides of thecore layer.
 8. The film of claim 6, wherein the polyalkyliminecondensation product is coated on at least one skin layer.
 9. The filmof claim 6, wherein the coating weight is less than 0.30 g/m².
 10. Thefilm of claim 1, wherein the coating has a solids content within therange of from 0.1% to 60%, by weight of the coating.
 11. The film ofclaim 1, wherein the coating comprises from 1% to 50 wt % anti-block byweight of the coating composition.
 12. The film of claim 1, wherein thepolyalkylimine has a weight average molecular weight of from 3,000 to2,000,000 amu.
 13. The film of claim 11, wherein the anti-block isoxidation treatment of the skin surface.
 14. The film of claim 1,wherein styrenic moieties are absent from the polyalkylimine.
 15. Thefilm of claim 1, further comprising a primer layer between the film andthe coating, the primer layer comprising a polyalkylamine having aweight average molecular weight of from 20,000 to 80,000 or 100,000 or150,000 or 200,000 or 500,000 amu and also comprising from 2 to 20 partsof a non-ionic surfactant.
 16. The film of claim 1, wherein from 0.1 or0.2 to 0.6 or 0.8 or 1.0 or 1.1 or 1.2 or 2.0 or 2.5 or 3.0amine-reactive equivalents (“ARE”) of amine-reactive molecules arecombined with the polyalkylimine.
 17. The film of claim 1, wherein thecondensation product is isolated from an aqueous diluent in solution ata pH of at least 8 prior to coating the film.
 18. The film of claim 1,wherein the amine-reactive molecule is selected from the groupconsisting of acetoacetoxyethyl methacrylate, methyl acetoacetonate,ethyl acetoacetonate, glycidyl methacrylate, methyl acrylate,acrylamide, acrylonitrile, 1,6-hexanediol diacrylate, 2-hydroxyethylacrylate, trimethylpropane triacrylate, pentaerythritol triacrylate, andmixtures thereof.
 19. A label comprising the film of claim 1.